The comparable concepts that have been proposed so far are of generally two different types. There is what can be called the float attachement type wherein floats are merely added to an existing vehicule or trailer. The U.S. Pat. Nos. 3,308,782 and 4,802,433 are typical examples of that category. In those U.S. patents, a pair of floats are merely attached to a house trailer or the like to operatively provide the required buoyancy for the trailer for operations as a house boat and are pivotable to an elevated stowed position to travel with the trailer. Such mere attachments have the floats always externally positioned relative to the carrying vehicule and are relatively unsightly.
There is also what can be called the elongated or combination type wherein the vehicule or trailer is custom made to integrate the floats or pontoons to it. The Canadian patent 1,016,411 and the U.S. Pat. No. 3,941,074 fall in that category. In these two patents, the wheels are attached to the pontoons and pivot with them between the trailer configuration and the boat configuration. This presents difficulties since the change from one configuration to the other must be made afloat where the wheels are free to pivot with the pontoons.